


Do you want to know a secret (do you promise not to tell)

by dearericbittle (dutchmoxie)



Category: Teen Wolf (TV)
Genre: Established Relationship, Fluff, Full Shift Werewolves, M/M, Stiles Stilinski Finds Out About Werewolves
Language: English
Status: Completed
Published: 2020-09-29
Updated: 2020-09-29
Packaged: 2021-03-07 22:28:42
Rating: Teen And Up Audiences
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 1,577
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/26715238
Author URL: https://archiveofourown.org/users/dutchmoxie/pseuds/dearericbittle
Summary: This is not how Stiles imagined his six month anniversary - shut up Derek, monthly anniversaries can totally be a thing if he says they are. For one, there was no wolf on his boyfriend’s couch. And then a secret sister? At least it’s a night they’ll never forget.
Relationships: Derek Hale/Stiles Stilinski
Comments: 38
Kudos: 457





	Do you want to know a secret (do you promise not to tell)

**Author's Note:**

> For fanficmakesmehappy over on Tumblr, who sent me an awesome prompt for my prompt fest: established Sterek, Stiles finds out about werewolves. 
> 
> This is short and sweet, but I hope it still hits the spot.

It’s kind of funny to Stiles that his six month anniversary - shut up Derek, monthly anniversaries can totally be a thing if he says they are - falls on the night of the full moon. Sure, it’s made it super hard for him to get the night off because shit always seems to get crazy around the full moon. That was a thing back in Beacon Hills, and it’s still a thing now he’s with the FBI. 

But he has so much overtime saved up that he doesn’t even have to call in any favors when he calls it a day way before everyone else. Which means he has still worked late, but not all night - he might be a bit late for dinner, but Derek now knows not to start turning on the stove until Stiles texts him that he’s on his way over. They’ve learned that much from their three month disappointment. That was a rough night for both of them. 

He texts when he’s in his car, like a good boy, and then immediately tosses his phone on the passenger seat afterwards, wanting to just get to Derek already. This has been a day that just would not end and allow him to get to the good part - which is Derek, naturally. Derek is most of the good parts of his life these days. 

Sure, he’s been keeping secrets, but judging by the few things Derek has told him about his past and the fact that his entire fucking family is dead? Stiles can’t blame him for being cautious, and he can totally be patient - shut up Derek, he totally can. When he’s properly motivated. 

“Der, I’m here,” he finds that the door is open when he arrives. “Happy anniversary. How sweet of you to leave the door open for - holy fucking shit!”

There is a wolf in Derek’s house. Like, an actual fucking wolf. It’s black and massive and fucking gorgeous, and apparently does not give a single flying fuck about how much vacuuming Derek is going to have to do because of all the shedding. 

Because apparently Stiles is having a breakdown, caring about shedding when there is a fucking wolf in Derek’s living room, draped all over the big couch. 

It looks up at him though, and it seems less than thrilled. The blue eyes are gorgeous, though. 

“Oh God, is this how I die?” Stiles manfully does not whimper. 

“Who’s the drama queen?” A girl wearing nothing but Stiles’ stud muffin shirt - so that’s where he left that - and panties walks out of the guest bedroom. “Derek, you didn’t tell me that you left the door open for total randos to come in. Did you forget to lock the door?”

It earns her a couple odd sounds from the wolf - why is that thing not trying to get out? Why is it not ripping Stiles’ throat out with its ginormous teeth? What is happening? 

Why is he sure that he has seen this girl before? 

“Why do you look familiar?” Stiles asks her in return. “Have we met?”

His priorities are fucked, because he’d rather figure out why Derek has a strange guest than worry about the fucking wolf that’s finally moving off the couch and in a distinctly Stiles-ish direction. As if it’s trying to protect him from the girl? Or eat Stiles first? Could be either. 

“I’m Derek’s sister,” the girl says. 

“Derek’s sister is dead,” Stiles knows better than to roll with that. “It’s how we met. When Laura was killed I was assigned to the case. Or well, I got myself involved, anyway.”

Look, Stiles hadn’t gone to that gruesome Jane Doe crime scene in the hopes of meeting the love of his life, but it has been a true fucking bonus. Asking Derek out after the case was closed (Peter Hale is still in a mental hospital that gives Stiles the fucking creeps) was kind of a shot in the dark, but to his great surprise Derek had actually said yes. And continued to say yes to all the follow-up dates. Stiles is still thrilled about that every single day. 

“Holy shit, you’re  _ Stiles _ ?” The girl looks less than impressed. “You’re Stiles and you’re still scared of Derek’s wolfy side? After six months?”

Wolfy side? Derek has a wolfy side? Is that wolf his pet? Is that what’s going on? Or is Derek a secret furry? Does he pretend to be a wolf on the full moon? That’s doable, Stiles can totally work with that. He can learn how to roll with it, maybe play along a bit even though the furry community is not that interesting to him. 

Though the wolf thing would explain the many, many bite marks and hickies Stiles has been trying to hide underneath his work clothes. He was almost tempted to buy a turtleneck at some point, but since he started dating Derek in the spring, it would just be really weird. 

And just when Stiles thinks he has a handle on things, everything changes again. 

“He didn’t know,” Derek is suddenly right fucking there - and very fucking naked. “Until you just opened your big mouth and told him all about it. Thanks, Cora.”

Just a second ago, there was a wolf there next to him. And while Stiles watches, the wolf just shifts and moves until there is a Derek instead. His Derek. The Derek. The Derek who is definitely a fucking werewolf. An actual fucking werewolf. 

Is it bad that he’s just relieved it’s not the furry thing? 

“She’s definitely your sister,” Stiles is kind of dying on the inside - and maybe on the outside too. 

And it’s not just because Derek is really fucking naked and even though Derek hasn’t been all that fussed about nudity lately, it’s still new enough for Stiles that he’s kind of really distracted by the play of Derek’s muscles and the perfect ass and dick - it took a while for Derek to feel comfortable enough with sex. More issues he doesn’t talk about but make Stiles want to hurt someone for daring to put their hands on Derek with less than great motives. 

“Stiles,” Derek reaches for him. 

“I’m so glad you’re a werewolf and not some weird furry,” Stiles lets himself be pulled closer. 

He’s pretty sure that the mystery sister is laughing at him, but he honestly couldn’t give less of a fuck about that because Derek is naked and holding him and he’s fucking smiling. And honestly, when Derek smiles, Stiles is suddenly capable of blocking out the rest of the world and looking at nothing but that. Because boy is that smile glorious. Derek should smile all the time. 

“I love you,” Derek says, for the first fucking time ever. 

“I know,” Stiles responds, because he’s always wanted to do that. 

According to Scott, he’s seen Star Wars far too many times - but then again Scott still hasn’t seen a single of the movies, so Stiles doesn’t think he can judge when he has no idea of how Stiles’ heart fucking soars when the theme starts playing and the words he’s read a hundred times before crawl across the screen. And when Han and Leia are, well, Han and Leia. 

Derek, though? Derek gets it. He may not be as excited about it as Stiles is, but he’s seen the movies a couple of times, most of them with Stiles. 

“You’re an idiot,” Derek huffs at him. 

“I love you,” Stiles tells him in return, because of course he does. 

Was there ever any doubt? Heck, Stiles has almost told Derek dozens, hundred, thousands of times already, but he’s kind of been waiting for Derek to say it first because he’s trying to do this thing where he respects Derek’s boundaries. Even the ones he hasn’t specifically stated out loud, just with his murder brows. Stiles is totally a good boyfriend. 

He’d be better if Derek would kiss him in front of his sister, though. 

Speaking of...

“You can tell me about the werewolf stuff later,” Stiles decides. “Right now you need to tell me about the secret sister. And then maybe we can celebrate our anniversary.” 

Sure, it might not be straight up romantic and sexy like Stiles had been hoping for when he got off work, but he’s totally adaptable. He can roll with the punches. And yeah, he reserves the right to have a bit of a freak-out about the werewolf thing at some point in the near future, but for now he just wants a bit of time to wrap his head around the sister thing - before they dive into the ‘werewolves are real and Stiles is dating one’ part of today’s surprises. 

“Six months is not an anniversary, Stiles,” Derek sighs heavily. “An anniversary is an annual thing. It’s in the name. And I refuse to use a word like monthiversary.” 

Well, he said it, so… Worth it. So fucking worth it. 

“You just did,” the sister points out, and maybe she isn’t awful after all. 

“I like you,” Stiles tells her. “Not as much as I like Derek, of course, because I love that sass-browed doofus, but you’re pretty cool. You can stay.” 

Judging by the look on Derek’s face, he’s lucky she doesn’t rip his throat out for that. With her teeth. Or her claws, probably. 

Werewolves have claws, right? Oh well, he’ll figure it out. He’s not going anywhere. 


End file.
